Pipe joint

ABSTRACT

A pipe connector having excellent pressure tightness and including a female connector ( 52 ), a male connector ( 54 ) and a retainer ( 56 ) is constructed so that the incomplete connection of the female connector ( 52 ) and the male connector ( 54 ) can be clearly perceived when the retainer is falsely locked. The retainer ( 56 ) has side walls ( 23   a   , 23   b ), first retaining lugs ( 58   a   , 58   b ) formed on the inner side of the side walls ( 23   a   , 23   b ), respectively, each having a first end edge ( 60   a ) that engages an annular ridge ( 20 ) formed on the male connector ( 54 ) to restrain the male connector ( 54 ) from axial backward movement when the retainer ( 56 ) is pushed into the female connector ( 52 ) with the male connector ( 54 ) completely inserted in the female connector ( 52 ), and a second end edge ( 60   b ) opposite to the first end edge ( 60   a ), and second retaining lugs ( 62   a   , 62   b ) formed on the inner side of the side walls ( 23   a   , 23   b ) and spaced at least a distance corresponding to the width of the annular ridge ( 20 ) apart from the first end edges ( 60   a ) of the first retaining lugs ( 58   a   , 58   b ), respectively. The second retaining lugs ( 62   a   , 62   b ) are in contact with a retaining member ( 32 ) fitted in a bore formed in the female connector ( 52 ) to prevent O rings ( 31   a   , 31   b ) fitted in the bore of the female connector ( 52 ) from coming off the bore of the female connector ( 52 ) to restrain the retaining member ( 32 ) from axial movement.

TECHNICAL FIELD

[0001] The present invention relates to a pipe connector and moreparticularly, to a quick-connect pipe connector for connecting pipes ofa fluid circuit included in a machine.

BACKGROUND ART

[0002] A pipe connecter called a quick connector is used prevalentlyfor, for example, connecting fuel pipes of automotive fuel supplysystems.

[0003] A quick connector includes, as principal components, a maleconnector to be connected to a pipe, a female connector to be connectedto a pipe, and a retainer for holding the male and the female connectortogether. The quick connector is able to connect the pipes without usingany fasteners, such as bolts, simply by inserting the male connector inthe female connector.

[0004] The type quick connecters of various structural designs have beendevised. The quick connector is required to have a function to achievefirm connection, a function to facilitate disconnection, a function toachieve high-sealed connection, and a function to avoid incompleteconnection. Incomplete connection is false connection in which the maleand the female connector are held together with a retainer with the maleconnector incompletely inserted in the female connector. An improvedquick connector constructed to prevent incomplete connection isdisclosed in, for example, U.S. Pat. No. 5,542,716 (JP-A No.50923/1998).

[0005] FIGS. 9 to 11 show a conventional quick connector.

[0006]FIG. 9 shows a female connector 12 and a male connector 14 of aquick connector 10, FIG. 10 shows a retainer 16, and FIG. 11 shows thefemale connector 12 and the male connector 14 completely connectedtogether by the retainer 16 in a longitudinal sectional view.

[0007] Basically, the quick connector 10 is designed so that theretainer 16 is unable to achieve a locking function when the same isinserted through an opening 19 in the female connector 14 unless themale connector 14 is completely inserted in the female connector 12 toprevent incomplete connection.

[0008] Referring to FIGS. 9 and 11, the female connector 12 has aconnecting part 13 to be pressed in a pipe, not shown, and a cylindricalhousing 15 formed integrally with the connecting part 13. The femaleconnector 12 is provided internally with a stepped, axial bore 17. Thehousing 15 has a connecting part 18 in which the male connector 14 isinserted. The connecting part 18 is provided with an opening 19 throughwhich the retainer is inserted in the connecting part 18. An opening 19a similar to the opening 19 is formed opposite to the opening 19 in theconnecting part 18. The housing 15 has the connecting part 18, a firstcylindrical part 21 a extending from the connecting part 18 and having adiameter smaller than that of the connecting part 18, and a secondcylindrical part 21 b extending from the first cylindrical part 21 a andhaving a diameter smaller than that of the first cylindrical part 21 a.

[0009] The male connector 14 is provided on its outer circumference withan annular ridge 20 at a predetermined distance from one end thereof.The annular ridge 20 engages in a groove formed in the retainer 16 whenthe retainer 16 is inserted in the connecting part 18 to restrain themale connector 14 from axial movement.

[0010] As shown in FIG. 10, the retainer 16 is a substantially U-shapedplastic member formed by molding. The retainer 16 has a body 22 havingopposite, parallel side walls 23 a and 23 b. Retaining lugs 24 a and 24b respectively having curved inner surfaces are formed on the innersurfaces of the side walls 23 a and 23 b, respectively. The retaininglugs 24 a and 24 b are capable of coming into close contact with theouter circumference of the male connector 14.

[0011] Referring to FIG. 11, the opening 19 of the female connector 12has an axial length L, and the retainer 16 has a length approximatelyequal to the length L of the opening 19. The opening 19 has a width,i.e., a dimension along a direction perpendicular to the axis of thefemale connector 12, substantially equal to the width of the retainer16, i.e., a dimension along a direction perpendicular to the axis ofretainer 16. Opposite axial ends of the opening 19 are defined by afront end wall 25 a and a rear end wall 25 b. The width L₁ of a gapbetween the front end wall 25 a, and the front end surfaces 26 a of theretaining lugs 24 a and 24 b of the retainer 16 is substantially equalto slightly greater than the width of the annular ridge 20 of the maleconnector 14. The positional relation between the annular ridge 20 ofthe male connector 14, and a space 34 between the front end surfaces 26a of the retaining lugs 24 a and 24 b of the retainer 16 is determinedas to meet the following condition. In a state where the male connector14 is inserted completely in the female connector 12 such that the frontend of the male connector 14 is pressed against a step between theconnecting part 13 and the second cylindrical part 21 b or the annularridge 20 is in contact with a top hat 32 serving as a pressing member,the annular ridge 20 is located in the space 34. When the annular ridge20 is thus located in the space 34, the retainer 16 can be pressedthrough the opening 19 in the connecting part 18 of the housing 15.

[0012] When the retainer 16 is held opposite to the opening 19, the maleconnector 14 is inserted in the female connector 12 so that the annularridge 20 is placed in the space 34, and then the retainer 16 is pushedthrough the opening 19 into the connecting part 18 of the femaleconnector 12, retaining ridges 30 a and 30 b formed along the loweredges of the side walls 23 a and 23 b on the outer side surfaces of theside walls 23 a and 23 b, respectively, engage the lower edges of sidewalls extending between the end walls 25 a and 25 b, respectively, toretain the retainer 16 in the connecting part 18 of the female connector12.

[0013] When the retainer 16 is set normally in place on the femaleconnector 12, the front end surfaces 26 a of the retaining lugs 24 a and24 b of the retainer 16 are in contact with the annular ridge 20 of themale connector 14 to restrain the male connector 14 from backward axialmovement. Thus, the female connector 12 and the male connector 14 arefirmly inseparably connected together.

[0014] A gap between the outer circumference of the male connector 14and the inner circumference of the first cylindrical part 21 a is sealedby O rings 31 a and 31 b. A spacer 33 is interposed between the O rings31 a and 31 b, and the O rings 31 a and 31 b are held in the gap betweenthe outer circumference of the male connector 14 and the innercircumference of the first cylindrical part 21 a and by the top hat 32.Thus, the O rings 31 a and 31 b are unable to come off the gap into theconnecting part 18.

[0015] The incomplete connection preventing mechanism of the pipeconnector shown in FIGS. 9 to 11 enables the retainer 16 to be insertedthrough the opening 19 into the connecting part 18 only when the annularridge 20 is placed in the space 34 to prevent to prevent the falseconnection of the female connector 12 and the male connector 14 due tothe incomplete insertion of the retainer 16 in the connecting part 18.

[0016] However, the following problem arises because practical pipeconnectors of this type respectively having different sizes need femaleconnectors and male connectors respectively having different sizes.

[0017] For example, male connectors 14 of different sizes differ fromeach other in the length between the annular ridge 20 and the front end.If the retainer 16 is inserted in the connecting part 18 beforeinserting the male connector 14 in the female connector 12, the annularridge 20 comes into contact with the rear ends 26 b of the retaininglugs 24 a and 24 b of the retainer 16 as shown in FIG. 12 and,consequently, the male connector 14 cannot be properly inserted in thefemale connector 12, and the female connector 12 and the male connector14 are connected incompletely. If a front part extending forward fromthe annular ridge 20 of the male connector 14 has a long length, thefront part of the male connector 14 will reach the O ring 31 b and the Oring 31 b will become effective. Consequently, it is possible that theincompletely connected pipe connector passes a pressure test andincomplete connection is overlooked. To avoid such incompleteconnection, the length of the retainer 16 must be increased so that therear end surfaces 26 b of the retaining lugs 24 a and 24 b are shiftedtoward the rear end of the female socket 12 to prevent the front partextending forward from the annular ridge 20 of the male connector 14from reaching the O ring 31 b, which increases the respective lengths ofthe housing 15 and the retainer 16.

[0018] To avoid increasing the length of the housing 15 of the femaleconnector 12 to be connected with a male connector having a long frontpart extending forward from an annular ridge 20, the position of theannular ridge 20 in a state where the male connector and the femaleconnector 12 are connected normally must be shifted backward withrespect to a direction in which the male connector is inserted in thefemale connector 12 to shift the front end surfaces 26 a of theretaining lugs 24 a and 24 b backward. Therefore, in some cases, thedistance L₂ between the front end wall 25 a of the female connector 12and the front end surfaces 26 a of the retaining lugs 24 a and 24 bbecomes unavoidably considerably long as shown in FIG. 13. When thefemale connector 12 is formed in a structure as shown in FIG. 13, it ispossible that the pressure tightness of the pipe connector is reducedand, when the pressure in pipes connected to the pipe connector becomeshigh, that the top hat 32 is forced into the connecting part 18, the Orings 31 a and 31 b are dislocated and the sealing effect thereof isnullified, even if the retainer 16 is engaged normally with the femaleconnector 12 to connect the female connector 12 and the male connectorcompletely.

[0019] The following problem arises even in a state shown in FIG. 11,where the retainer 16 functions normally and the female connector 12 andthe male connector 14 are completely connected together. When piping isarranged such that the pipe connector 10 shown in FIG. 11 is set upsidedown, it is possible that water formed by condensation or the likecollects in the space 34 between the front end wall 25 a, and the frontend surfaces 27 a of the retaining lugs 24 a and 24 b, and the femaleconnector 12 will be corroded if the female connector 12 is formed of ametal.

[0020] The foregoing problems in the prior art are attributable mostlyto false connection of the female connector 12 and the male connector 14incompletely inserted in the female connector by the retainer 16.Another problem in the prior art is the false assembly of the femaleconnector 12 and the retainer 16.

[0021] When shipping a conventional quick connector, the femaleconnector 12 and the retainer 16 are wrongly combined by false assembly.

[0022] Some conventional quick connector 10′ includes a directionalretainer 16 which must be set in a specific position in a femaleconnector 12 as shown in FIG. 14. In the conventional connector 10′shown in FIG. 14, the rear end surfaces 26 b of retaining lugs 24 a and24 b not in contact with an annular ridge 20 formed on a male connector14 are formed so as to be in contact flat with a rear end wall 25 b.Therefore, the retainer 16 must be inserted through an opening in thefemale connector 12 with the front end surfaces 26 a, which engages theannular ridge 20, of the retaining lugs 24 a and 24 b facing the front.

[0023] As shown in FIG. 15(a), the side walls of the connecting part 18of a female connector 12 are provided in their horizontal upper edgeswith recesses 37, and the side walls 23 a and 23 b of a retainer 16 areprovided with projections 38 which engage in the recesses 37, on theirouter surfaces, respectively. The projections 38 are formed at positionssomewhat behind the middle points of the side walls 23 a and 23 b,respectively, to make a distinction between the front and the rear endof the retainer 16 in appearance, and the positions of the recesses 37are determined so as to correspond to those of the projections 38.

[0024]FIG. 15(a) shows the female connector 12 and the retainer 16 in acorrect assembly. When the quick connector 10′ is shipped from afactory, the retainer 16 half-inserted in the female connector 12 suchthat an upper half part of the retainer 16 protrudes from the connectingpart 18 to prevent false connection.

[0025] However, it often occurs that the retainer 16 is inserted wronglyin the connecting part 18 in a reverse position as shown in FIG. 15(b).However, the difference between a correct assembly of the femaleconnector 12 and the retainer 16 and a wrong assembly of the same is notso significant as to enable making a clear distinction between thecorrect and the wrong assembly at a glance and, consequently, wrongassemblies are overlooked and are delivered to customers.

[0026] If the retainer 16 is reversed, the retainer 16 is unable to locktogether the female connector 12 and a male connector 14 inserted in thefemale connector 12 by pushing the retainer 16 into the female connector12 because the projections 38 rest on the horizontal upper edges 16 a ofthe side walls of the connecting part 18, so that false connection canbe avoided. In such a case, the user needs additional work for pullingout the retainer 16 from the female connector 12 and inserting theretainer 16 in a correct position in the female connector 12.

[0027] Moreover, it is possible that the retainer 16 is inserted throughthe other opening 19 a on the side of lower horizontal edges 16 b of theside walls not provided with any recess in the female connector 12 asindicated by two-dot chain lines in FIG. 15(b).

DISCLOSURE OF THE INVENTION

[0028] Accordingly, it is a first object of the present invention tosolve the foregoing problems in the prior art and to provide a pipeconnector including a female connector, a male connector and a retainer,having structure that enables clear recognition of incomplete connectionof the female connector and the male connector when the retainer lockstogether the female and the male connector falsely, and excellent inpressure-proof strength.

[0029] A second object of the present invention is to provide a pipeconnector including a female connector, a male connector, and a retainerthat is never combined falsely with the female connector for shippingfrom a factory.

[0030] According to one aspect of the present invention, a pipeconnector includes: a male connector provided with an annular ridge; afemale connector having a housing provided with an opening; and aU-shaped retainer having a body, and opposite side walls to be insertedthrough the opening in the housing in a direction perpendicular to anaxial direction to lock together the male and the female connector;wherein a false connection preventing structure is formed to make theretainer unable to be pushed through the opening into the housing tolock together the male and the female connector when the male connectoris inserted incompletely in the female connector; the retainer isprovided with first retaining lugs formed on the inner side of the sidewalls, each having a first end edge that engages the annular ridge whenthe male connector is inserted completely in the female connector andthe retainer is inserted in the housing of the female connector torestrain the male connector from axial backward movement, and a secondend edge opposite to the first end edge, and second retaining lugsspaced at least a distance corresponding to the width of the annularridge apart from the first end edges of the first retaining lugs,respectively; and the second retaining lugs are in contact with aretaining member fitted in a bore formed in the female connector toprevent O rings fitted in the bore of the female connector from comingoff the bore of the female connector to restrain the retaining memberfrom axial movement.

[0031] According to another aspect of the present invention, a pipeconnector includes: a male connector provided with an annular ridge; afemale connector having a housing provided with an opening; and aU-shaped retainer having a body, and opposite side walls to be insertedthrough the opening in the housing in a direction perpendicular to anaxial direction to lock together the male and the female connector;wherein a false connection preventing structure is formed to make theretainer unable to be pushed through the opening into the housing tolock together the male and the female connector when the male connectoris inserted incompletely in the female connector; and the retainer isprovided with retaining lugs formed on the inner side of the side walls,each having a first end edge that engages the annular ridge when themale connector is inserted completely in the female connector and theretainer is inserted in the housing of the female connector to restrainthe male connector from axial backward movement, and a second end edgeopposite to the first end edge, and a false assembly preventing meansfor preventing the retainer from being combined with the femaleconnector when the retainer is pushed to insert the same through theopening in the housing in a longitudinally reversed position.

BRIEF DESCRIPTION OF THE DRAWINGS

[0032]FIG. 1 is a longitudinal sectional view of a pipe connector in afirst embodiment according to the present invention;

[0033]FIG. 2 is a perspective view of a retainer included in the pipeconnector;

[0034]FIG. 3 is a sectional view taken on line III-III in FIG. 2;

[0035]FIG. 4 is a sectional view taken on line IV-IV in FIG. 3;

[0036]FIG. 5 is a longitudinal sectional view of the pipe connectorshown in FIG. 1 in a state where the female and the male connector afalsely connected by the retainer;

[0037]FIG. 6 is a sectional view of a retainer in a modification;

[0038]FIG. 7 is a perspective view of an essential part of a pipeconnector in a second embodiment according to the present invention;

[0039] FIGS. 8(a), 8(b) and 8(c) are views of assistance in explainingthe function of the pipe connector in the second embodiment to preventfalse combination of a retainer with a female connector;

[0040]FIG. 9 is a perspective view of a conventional quick-connectionpipe connector;

[0041]FIG. 10 is a perspective view of a retainer included in theconventional pipe connector shown in FIG. 9;

[0042]FIG. 11 is a longitudinal sectional view of the conventional pipeconnector;

[0043]FIG. 12 is a longitudinal sectional view of the conventional pipeconnector in a falsely connected state;

[0044]FIG. 13 is a longitudinal sectional view of another conventionalpipe connector;

[0045]FIG. 14 is a longitudinal sectional view of a third conventionalpipe connector;

[0046] FIGS. 15(a) and 15(b) are views of assistance in explaining thefalse insertion of a retainer in a female connector in a conventionalpipe connector; and

[0047] FIGS. 16(a) and 16(b) are views of assistance in explaining thefalse insertion of a male connector in a female connector in aconventional pipe connector.

BEST MODE FOR CARRYING OUT THE INVENTION

[0048] Pipe connectors in preferred embodiments according to the presentinvention will be described with reference to the accompanying drawings;

[0049] First Embodiment

[0050]FIG. 1 is a longitudinal sectional view of a pipe connector 50 ina first embodiment according to the present invention. A femaleconnector 52, a male connector 54 and a retainer 56 included in the pipeconnector 50 have parts similar to those of the female connector 12, themale connector 14 and the retainer 16 of the conventional pipe connectorshown in FIGS. 9 and 10. The parts of the female connector 52, the maleconnector 54 and the retainer 56 similar to those of the femaleconnector 12, the male connector 14 and the retainer 16 of theconventional pipe connector are denoted by the same reference charactersand the description thereof will be omitted.

[0051] As shown in FIGS. 2 and 3, the retainer 56 is a U-shaped memberformed in a single piece by molding a plastic material. The retainer 56has a body 22, and opposite, parallel side walls 23 a and 23 b. The sidewalls 23 a and 23 b are integrally provided with first retaining lugs 58a and 58 b respectively having curved inner surfaces. The retaining lugs58 a and 58 b come into close contact with the outer circumference ofthe male connector 54.

[0052] Each of the first retaining lugs 58 a and 58 b of the retainer 56has a first end edge 60 a, i.e., an end edge on the front side withrespect to a direction in which the male connector 54 is inserted in thefemale connector 52, a second end edge 60 b, i.e., an end edge on theback side. The first end edge 60 a engages an annular ridge 20 formed onthe male connector 54 when the male connector 54 is inserted completelyin the female connector 52 to restrain the male connector 54 from axial,backward movement.

[0053] The retainer 56 is integrally provided, in addition to the firstretaining lugs 58 a and 58 b, with second retaining lugs 62 a and 62 bas shown in FIGS. 2 and 4. The second retaining lugs 62 a and 62 b havecurved inner surfaces conforming to the outer circumference of the maleconnector 54. The second retaining lugs 62 a and 62 b are spaced adistance greater than the width of the annular ridge 20 of the maleconnector 54 apart. As shown in FIG. 1, the retainer 56 has a lengthapproximately equal to the length L, i.e., a dimension along the axis ofthe female connector 54, of an opening 19 formed in the female connector52, and a width approximately equal to the width, i.e., a dimension in adirection perpendicular to the axis of the female connector 52, of theopening 19. When the male connector 54 is inserted completely in thefemale connector 52 so that the front end of the male connector 54 comesinto contact with a step formed in a bore 17 between a connecting part17 and a second cylindrical part 21 b, the annular ridge 20 is locatedin a space corresponding to a space 64 between the first end edges 60 aof the first retaining lugs 58 a and 58 b of the retainer 56, and thesecond retaining lugs 62 a and 62 b. In this state, the retainer 56 canbe pushed in the female connector 52. When the retainer 56 is fullyinserted in the female connector 52, retaining ridges 30 a and 30 bformed on the side walls 23 a and 23 b of the retainer 56 engage thehorizontal lower edges of side walls, not shown, defining the opening 19to lock the retainer 56 in place.

[0054] In a state where the retainer 56 is locked in place on the femaleconnector 52, the first end edges 60 a of the first retaining lugs 58 aand 58 b engage the annular ridge 20 of the male connector 54 as shownin FIG. 1. Thus, the male connector 54 cannot be extracted from thefemale connector 52 even if a pulling force is exerted on the maleconnector 54.

[0055] When the retainer 56 is locked, and the female connector 52 andthe male connector 54 are completely connected together, the secondretaining lugs 62 a and 62 b of the retainer 56 are in contact with atop hat 32 serving as a retaining ring for holding in place O rings 31 aand 31 b fitted in the bore of the first cylindrical part 21 a to holdthe top hat 32 in place.

[0056] When the pressure in a pipe connected to the pipe connector 50increases, the pressure tends to force the top hat 32 out of the firstcylindrical part 21 a into a connecting part 18 provided with theopening 19. However, the top hat 32 is unable to be pushed into theconnecting part 18 because the top hat 32 is restrained from axialmovement by the second retaining lugs 62 a and 62 b of the retainer 56.Therefore, the O rings 31 a and 31 b will not be dislocated, the sealingeffect thereof will not be nullified, and hence the pipe connector 50 isable to maintain high pressure tightness.

[0057]FIG. 5 shows the positional relation between the male connector 54and the retainer 56 when the male connector 54 is inserted in the femaleconnector 52 after pushing the retainer 56 in the female connector 52and locking the retainer 56 on the female connector 52.

[0058] The annular ridge 20 of the male connector 54 is in contact withsecond end edges 60 b of the first retaining lugs 58 a and 58 b of theretainer 56 and hence the male connector 54 cannot be inserted anyfurther in the female connector 52. The length of a front part extendingforward from the annular ridge 20 of the male connector 54, the lengthof the retainer 56, and the position of the second end edges 60 b aredetermined so that the front end of the front part of the male connector54 is unable to reach the O rings 31 a and 31 b in the state shown inFIG. 5.

[0059] Therefore, if the retainer 56 is falsely locked with the maleconnector 54 inserted incompletely in the female connector 52 as shownin FIG. 5, the O rings 31 a and 31 b are ineffective, and hence, if afluid flows through the pipe, the fluid leaks necessarily from the pipeconnector 50. Thus, an undesirable condition, in which the O rings 31 aand 31 b are able to exercise a sealing function with the femaleconnector 52 and the male connector 54 incompletely connected together,can be prevented.

[0060] Preferably, the body 22 of the retainer 56 is provided with adrain groove 66 formed between the second retaining lugs 62 a and 62 bas shown in FIG. 2. As shown in FIG. 1, the drain groove 66 communicateswith the space 64 between the first retaining lugs 58 a and 58 b, andthe second retaining lugs 62 a and 62 b. When piping is arranged suchthat the pipe connector 50 shown in FIG. 1 is set upside down, water canbe drained from the space 64 through the draining groove 66 and anywater stays in the space 64. Therefore, even if the male connector 54 isa metal pipe, the corrosion of the male connector 54 by water can beprevented.

[0061] Referring to FIG. 6 showing a retainer 56 in a modification ofthe retainer 56 shown in FIG. 2, the retainer 56 in the modification hasside walls 23 a and 23 b provided with anchoring structures,respectively. The anchoring structure of the side wall 23 a includes alower retaining ridge 67 a and an upper retaining ridge 68 a, and theanchoring structure of the side wall 23 b includes a lower retainingridge 67 b and an upper retaining ridge 68 b. A female connector 52 hasa connecting part 18 provided with side walls 70 a and 70 b. The lowerretaining ridges 67 a and 67 b engage the lower edges of the side walls70 a and 70 b, and the upper retaining ridges 68 a and 68 b engage ingrooves 772 a and 72 b formed in the inner surfaces of the side walls 70a and 70 b, respectively.

[0062] Since each of the anchoring structures has the two retainingridges, i.e., the upper and the lower retaining ridge, the retainer 56can be locked in place by the retaining structures even if one of thetwo retaining ridges is broken or is not formed correctly due to shortshot in the molding process.

[0063] Second Embodiment

[0064] A pipe connector in a second embodiment according to the presentinvention will be described with reference to FIGS. 7 and 8.

[0065] The pipe connector in the second embodiment has a false assemblypreventing structure for preventing the false assembly of a femaleconnector 52 and a retainer 56. The female connector 52 and the retainer56 are basically identical in construction with those of the pipeconnector in the first embodiment. Therefore parts of the femaleconnector 52 and the retainer 56 of the pipe connector in the secondembodiment similar to those of the pipe connector in the firstembodiment are denoted by the same reference characters and thedescription thereof will be omitted. Only the false assembly preventingstructure will be described.

[0066] Referring to FIG. 7, portions of end edges of side walls 23 a and23 b on the side of the second end edges 60 b of first retaining lugs 58a and 85 b formed in the retainer 56 are cut in an axial depth t to formrecesses 73 a and 73 b. End portions of the first retaining lugs 58 aand 58 b corresponding to the recesses 73 a and 73 b project from aplane including the end edges of the side walls 23 a and 23 b. The widthof a part including the recesses 73 a and 73 b of the retainer 56 issmaller than the width w of the retainer 56. Second retaining lugs 62 aand 62 b, not shown in FIG. 7, similar to those shown in FIG. 2 areformed on the inner surfaces of the side walls 23 a and 23 b of theretainer 56.

[0067] Square projections 74 a and 74 b of dimensions corresponding tothose of the recesses 73 a and 73 b are formed integrally with aconnecting part 18 of the female connector 52 in the corners of one endof an opening 19. The square projections 74 a and 74 b have a length t,i.e., a dimension in the direction of the axis of the female connector52. The distance between the square projections 74 a and 74 b is smallerthan the distance between the side walls 70 a and 70 b of the connectingpart 18.

[0068]FIG. 8(a) is a side elevation of an assembly of the femaleconnector 52, and the retainer 56 put on the female connector 52 in acorrect direction. The combination of the female connector 52 and theretainer 56 put on the female connector 52 so as to protrude from thefemale connector 52 as shown in FIG. 8(a) is shipped from the factory.FIG. 8(b) is a top plan view of the combination of the female connector52 and the retainer 56 shown in FIG. 8(a). The recesses 73 a and 73 bare positioned in the opening 19 of the female connector 52 as shown inFIG. 8(b) when the retainer 56 is correctly oriented with respect to thefemale connector 52. Since the square projections 74 a and 74 b areengaged in the recesses 73 a and 73 b, respectively, in a state shown inFIG. 8(b), the retainer 56 can be pushed through the opening 19 into thefemale connector 52 to lock the retainer 56 in place on the femaleconnector 52.

[0069]FIG. 8(c) shows a state where the retainer 56 is disposed in alongitudinally reverse direction relative to the opening 19. When theretainer 56 in the state shown in FIG. 8(c) is pushed, the retainer 56is pushed forward by a distance corresponding to the length t of thesquare projections 74 a and 74 b because the distance between the squareprojections 74 a and 74 b is smaller than the width of the retainer 56.Consequently, the parts of the first retaining lugs 58 a and 58 b aroundthe first end edges 60 b projecting from a plane including the end edgesof the side walls 23 a and 23 b hit on a front end wall defining theopening 19 of the female connector 52, so that the retainer 56 cannot becombined with the female connector 52. Thus, the false combination ofthe retainer 56 and the female connector 52 can be prevented withreliability.

[0070] The combination of the recesses 73 a and 73 b, and the squareprojections 74 a and 74 b may prevent, in addition to the false assemblyof the female connector 52 and the retainer 56, the insertion of theretainer 56 through an opening 19 a opposite the opening 19 providedwith the square projections 74 a and 74 b in the female connector 52.

[0071] As shown in FIG. 7, a longitudinal bar 76 is formed integrallywith the connecting part 18 of the female connector 52 so as to extendin a middle part of the opening 19 a of the connecting part 18 toprevent the insertion of the retainer 56 through the opening 19 a in thefemale connector 52. Thus, the wrong insertion of the retainer 56 from awrong direction in the female connector 52 can be surely prevented.

[0072] FIGS. 16(a) and 16(b) show examples of false assembly of theconventional quick-connection pipe connector 10 shown in FIG. 9; thefront end part of the male connector 14 is falsely extended through theopening 19 a through which the retainer 16 is not inserted in the femaleconnector 12 in FIG. 16(a), and the male connector 14 is biased towardthe opening 19 a in a state where the retainer 16 is falsely locked inFIG. 16(b). These false states can be prevented by the bar 76 extendedin the opening 19 a.

[0073] As apparent from the foregoing description, according to thepresent invention, the O ring retaining member is restrained from comingoff the bore of the female connector to enhance the pressure tightnessof the pipe connector considerably, the incomplete connection of thefemale and the male connector can be clearly perceived because the frontend part of the male connector is unable to engage the O rings when theretainer is falsely locked, and the use of the pipe connector with thefemale and the male connector incompletely connected can be prevented.

[0074] The false combination of the retainer with the female connectorcan be surely avoided when shipping the pipe connector from the factory.

1. A pipe connector comprising: a male connector provided with anannular ridge; a female connector having a housing provided with anopening; and a U-shaped retainer having a body, and opposite side wallsto be inserted through the opening in the housing in a directionperpendicular to an axial direction to lock together the male and thefemale connector; wherein a false connection preventing structure isformed to make the retainer unable to be pushed through the opening intothe housing to lock together the male and the female connector when themale connector is inserted incompletely in the female connector; theretainer is provided with first retaining lugs formed on the inner sideof the side walls, each having a first end edge that engages the annularridge when the male connector is inserted completely in the femaleconnector and the retainer is inserted in the housing of the femaleconnector to restrain the male connector from axial backward movement,and a second end edge opposite to the first end edge, and secondretaining lugs spaced at least a distance corresponding to the width ofthe annular ridge apart from the first end edges of the first retaininglugs, respectively; and the second retaining lugs are in contact with aretaining member fitted in a bore formed in the female connector toprevent O rings fitted in the bore of the female connector from comingoff the bore of the female connector to restrain the retaining memberfrom axial movement.
 2. The pipe connector according to claim 1, whereinthe second end edges of the first retaining lugs engage the annularridge of the male connector to obstruct the further insertion of themale connector in the female connector and to prevent a front end partof the male connector from reaching the O ring when a front part of themale connector is inserted in the female connector after the retainerhas been locked in place on the female connector.
 3. The pipe connectoraccording to claim 1, wherein the retainer is provided with a drain holefor draining water collected in a space between the first and the secondretaining lugs.
 4. The pipe connector according to claim 1, wherein eachof the side walls of the retainer has an anchoring part provided with aretaining ridge capable of engaging the female connector to lock theretainer in place.
 5. The pipe connector according to claim 4, whereinthe retaining ridge of each anchoring part is formed at positions at twodifferent levels.
 6. (Amended) The pipe connector according to claim 1further comprising a false assembly preventing means for preventing theretainer from inserting into the opening and from being held on theopening and preventing the false assembly of the retainer and the femaleconnector, when the retainer is inserted through the opening in thefemale connector in a longitudinally reverse position.
 7. The pipeconnector according to claim 6, wherein the false assembly preventingmeans includes: recesses formed in rear end edges of the side walls sothat rear end parts having the second end edges of the first retaininglugs project from a plane including the rear end edges of the sidewalls; and square projections having dimensions corresponding to thoseof the recesses, and protruding into the opening from corners of theopening.
 8. The pipe connector according to claim 6, wherein the falseassembly preventing structure includes a longitudinal bar formed so asto extend in a middle part of a second opening opposite to the openingto prevent the insertion of the retainer through the second opening inthe female connector.
 9. A pipe connector comprising: a male connectorprovided with an annular ridge; a female connector having a housingprovided with an opening; and a U-shaped retainer having a body, andopposite side walls to be inserted through the opening in the housing ina direction perpendicular to an axial direction to lock together themale and the female connector; wherein a false connection preventingstructure is formed to make the retainer unable to be pushed through theopening into the housing to lock together the male and the femaleconnector when the male connector is inserted incompletely in the femaleconnector; and the retainer is provided with retaining lugs formed onthe inner side of the side walls, each having a first end edge thatengages the annular ridge when the male connector is inserted completelyin the female connector and the retainer is inserted in the housing ofthe female connector to restrain the male connector from axial backwardmovement, and a second end edge opposite to the first end edge, and afalse assembly preventing means for preventing the retainer from beingcombined with the female connector when the retainer is pushed to insertthe same through the opening in the housing in a longitudinally reversedposition.